"The serious crashes have gone down," at the camera-monitored intersections at which Mercury Boulevard, Oyster Point Road and Denbigh Boulevard cross Jefferson Avenue, he said. Scott is one of two officers who reviews potential violations captured on photos and video by the system before citations are issued.

"Rear-enders are up, but serious injuries and fatals are down," he added. Before the cameras were installed, there were 81 rear-end collisions at the three intersections. Afterward, there were 96, each over a two-year period, according to Jan. 10, 2013 report by the city traffic engineers.

But critics question the effectiveness of the system. The Wisconsin-based National Motorists Association, an advocacy group, opposes their use in statements on its website, saying they cause crashes and inconvenience drivers. J.J. Bahen, who compiled a report for the advocacy group, agreed in a recent letter to the Virginia House Transportation Committee in support of repealing the state's red-light camera law. Bahen said the cameras increase collisions.

The city's traffic engineers say the data collected supports both Scott's and the Bahen's contentions.

Engineering director Everett Skipper echoed Scott, saying the city has seen more rear-end collisions at the intersections since the cameras were installed in 2010, but fewer serious collisions. He called the statistics "kind of marginal," and said the city renewed its contract with Redflex in June 2013 to gather one more year of data to determine the program's effectiveness.

Bump in crash statistics

Scott is a member of the department's crash team and investigates fatal collisions. He said fatalities have dropped at the three intersections since 2010, and he attributes that in part to the cameras. Scott said the system is not designed to punish drivers, "it's to curb behavior."

He and police department spokesman Lou Thurston said the data shows an uptick in rear-end collisions, but he attributes that to aggressive driving.

But Bahen said he is concerned about the increase in rear-end collisions, which he attributes to drivers' concerns about receiving a citation. A driver is more likely to hit the brakes quickly, setting in motion a chain reaction, he said.

Skipper said the increase in rear-end collisions was expected, but the engineering department has noted a decline in angle accidents, such as T-bones, that cause extensive injury and damage.

The city's report compares collisions two years before and after the cameras were installed and supports Skipper's claim.

The report states that the total number of collisions increased by 6 percent on camera-monitored lanes at the three intersections after the system was installed, but crashes directly related to running a red light in those lanes decreased by 50 percent.

Jefferson Avenue and Oyster Point Road was the intersection with the highest volume and highest number of collisions, with 53 total crashes in the two years before the cameras were installed and 59 in the years after. The greatest bump was in rear-end crashes, from 33 to 42. The number of right-angle, or T-bone collisions dropped from 4 to 3.

Jefferson Avenue and Mercury Boulevard posted the second highest totals, and the number of collisions dropped from 56 before the cameras were installed to 53 after. The number of rear-end collisions increased from 30 to 32, and the number of T-bone collisions went up, from 5 to 11.

Denbigh Boulevard and Jefferson Avenue had the fewest collisions with 38 before the cameras and 39 after. The number of T-bone collisions dropped, 9 to 6, but the number of rear-enders bumped from 18 to 22.

Skipper said the numbers were close to expectations, but were inconclusive. "We're still evaluating," he said.

Company in controversy

The city decided in 2008 to install a red-light camera system to "gain compliance with traffic signals, which will significantly contribute to public safety," according to its website. By law, Newport News is eligible for up to 18 cameras, but officials said they chose the three intersections because they had the highest accident rates, the highest rates of red light infractions and because police officers had difficulty issuing citations.

"There were times we had to let violators go because it was not safe to follow them and pull them over," Scott said.

Redflex was one of five companies to submit proposals to install and manage a red-light system in the city in 2008, with the goal of improving traffic safety. The city awarded the Phoenix-based company a three-year contract in 2009 for its Photo Safe system.